The United Nations is scrambling to get Yemen peace talks in Geneva moving with both the exiled government and the Iran-backed Yemeni rebels accusing each other of trying to sabotage the process.

The UN special envoy to Yemen, Ismail Ould Cheikh Ahmed, began shuttle diplomacy in Geneva trying to bridge differences between warring parties, but both sides still refuse to sit at the same table and spell out clashing agendas.

Al Jazeera’s Hashem Ahelbarra, reporting from Geneva, said on Wednesday that both delegations are unhappy with the lack of progress during the talks.

“The delegation representing the Yemeni government met with ambassadors from the EU and said that they are not happy with the way the talks are handled and that there is no progress this afternoon.

“This is a very critical moment – we do understand that the Houthi representatives at the same time said that they are also not happy with the way things are handled.

Ahelbarra also said the Houthis are waiting for an answer from the UN envoy about the make up of their representation to be able to start the talks.

“They have not been able to bring the two parties to move forward or to implement a humanitarian truce.

“They do not seem to have very much different options, they had high hopes that they could convince different factions of a two week human truce to allow international aid to flow into Yemen.

“If that happens they would like to talk about critical issues like how to implement a cease fire accross the country and they would like to see Houthis pull out from cities they have captured.”

The Houthis said they can not leave areas they have captured because they think al-Qaeda will take them and they insist to see some guarantee – not by international monitors but by professional Yemeni army.

Yemeni Foreign Minister Riad Yassin repeated the exiled government’s stand that a rebel pullout was non-negotiable.

“We are demanding their retreat from all the provinces to conclude a ceasefire or truce in keeping with Resolution 226 of the Security Council,” he said.

UN Secretary-General Ban Ki-moon formally opened the Geneva parley on Monday calling for a humanitarian truce in Yemen, already suffering severe poverty and unemployment, to coincide with the start of the Muslim holy month of Ramadan.

Yemen has been wracked by conflict between Iran-backed Shiite rebels and troops loyal to exiled President Abedrabbo Mansour Hadi, who fled to Saudi Arabia in February.

Global powers are keen for a speedy resolution, fearing the growing power of Al-Qaeda in the Arabian Peninsula, the Yemeni branch of the jihadist network that has taken advantage of the chaos to seize territory.

The UN has described Yemen’s humanitarian crisis as “catastrophic”, with 80 percent of the population — 20 million people — in need of aid.

The US said onTuesday that the UN talks were “the best way forward for Yemenis” with a political solution “the only way to resolve the crisis”.

“We encourage Yemenis participating in the talks to work towards a rapid resumption of the Yemeni political transition process,” the State Department’s press office director Jeff Rathke told AFP news agency. Al Jazeera